Analog Devices Inc. LTC1326CMS8#PBF

Overview

LTC1326CMS8#PBF from Analog Devices (formerly Linear Technology) is a micropower precision triple supply monitor IC designed for systems requiring simultaneous monitoring of 2.5V, 3.3V, and adjustable supplies. It delivers ±0.75% threshold accuracy, 20µA typical supply current, 200ms internal reset delay, active-low/open-drain RST and SRST outputs, and push-button reset functionality - enabling reliable power-on, brownout, and manual reset control in portable and battery-powered equipment.

For engineers reviewing the LTC1326CMS8#PBF datasheet, LTC1326CMS8#PBF pinout, LTC1326CMS8#PBF application, or LTC1326CMS8#PBF equivalent, key selection considerations include its guaranteed reset assertion down to VCC3 ≥ 1V or VCC25 ≥ 1V, glitch-immune comparators with 13µs response time, dual-mode reset (soft/hard), and MSOP-8 package compatibility with space-constrained embedded designs.

Technical Context

The LTC1326CMS8#PBF implements three independent high-accuracy voltage comparators - one each for VCC25 (2.5V nominal), VCC3 (3.3V nominal), and VCCA (adjustable ~1V threshold) - with internal 200ms reset timer and PBR-triggered soft-reset logic. Its gate-drive architecture selects the highest valid supply (VCC3 or VCC25) to drive the RST output FET, ensuring robust low-state operation even during asymmetric power-up sequences.

It features weak internal 6µA pull-ups on RST/SRST, supports OR-tied reset sources, includes 20ms debounce on PBR, and provides override modes to configure it as dual- or single-supply monitor. The part guarantees correct reset state across –40°C to 85°C and maintains <0.4V VOL at 100µA sink current down to 1V supply.

Key Specifications

Pinout & Package

Package: 8-lead plastic MSOP (MS8), 3.0mm × 3.0mm body, 0.65mm pitch, RoHS-compliant #PBF marking.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar triple-supply monitoring applications.

Compared with LTC1726-2.5 and LTC2903, the LTC1326CMS8#PBF uniquely balances ultra-low power (20µA), high accuracy (±0.75%), integrated soft/hard reset, and industrial temperature support - making it optimal for battery-powered and mission-critical embedded systems where reliability and efficiency are co-prioritized.

Availability

LTC1326CMS8#PBF is available at Aetrix Electronics and suitable for desktop computers, intelligent instruments, and industrial embedded controllers requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant packaging.

Supply support for LTC1326CMS8#PBF includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Analog Devices acquired Linear Technology in 2017 and maintains full product support, documentation, and manufacturing continuity for legacy Linear parts including the LTC1326 series.

The LTC1326 family was designed specifically for micropower, high-accuracy monitoring of multiple supply rails in portable, battery-operated, and industrial systems - emphasizing low quiescent current, glitch immunity, and flexible reset configuration.

FAQ

What is the primary function of the LTC1326CMS8#PBF?

The LTC1326CMS8#PBF is a micropower triple supply monitor IC that simultaneously supervises 2.5V, 3.3V, and an adjustable supply (typically ~1V). It generates a reliable reset signal during power-up, brownout, or manual push-button events. Its design ensures deterministic behavior with ±0.75% threshold accuracy, 20µA supply current, and guaranteed reset assertion down to VCC3 ≥ 1V or VCC25 ≥ 1V - making the LTC1326CMS8#PBF ideal for portable and industrial embedded systems demanding high reliability and low power consumption.

How does the LTC1326CMS8#PBF handle power sequencing between VCC25 and VCC3?

The LTC1326CMS8#PBF uses an internal power-detect/gate-drive circuit that automatically selects the higher of VCC25 or VCC3 to drive the RST output FET. This ensures the RST pin remains asserted low as soon as either supply reaches 1V, eliminating the need for external diode-OR networks. During asymmetric power-up - such as VCC25 ramping before VCC3 - the LTC1326CMS8#PBF maintains correct reset state without glitches, satisfying strict sequencing requirements in FPGA and microprocessor applications.

Can the LTC1326CMS8#PBF be used as a dual-supply or single-supply monitor?

Yes, the LTC1326CMS8#PBF supports configurable operation via pin-strapping overrides. VCCA can be tied to VCC3 or VCC25 to disable its comparator. For dual-supply use, VCC25 may be tied to VCC3, effectively monitoring only 3.3V and the adjustable rail. The LTC1326CMS8#PBF also includes internal override logic that disables VCC25 monitoring when its voltage matches VCC3 within ±25mV below ~4.15V - allowing flexible reconfiguration without hardware changes.

What is the difference between RST and SRST outputs on the LTC1326CMS8#PBF?

RST is the primary active-low open-drain reset output, asserted during power-up, brownout, or long (>2s) PBR press, with a 200ms timeout. SRST is the "soft reset" output, asserting for only 100µs after short (<2s) PBR release - enabling non-disruptive processor reset that preserves DRAM refresh cycles. Both outputs feature weak 6µA internal pull-ups to VCC3 and support OR-tying with other reset sources. The LTC1326CMS8#PBF thus provides two distinct reset modes optimized for different system recovery scenarios.

Does the LTC1326CMS8#PBF require external components for basic operation?

Yes - the LTC1326CMS8#PBF requires a minimum 0.1µF ceramic bypass capacitor from VCC3 to GND for stable operation. External pull-up resistors (e.g., 4.7kΩ) on RST/SRST are recommended for faster rise times, though not strictly required due to internal 6µA pull-ups. No external timing components are needed, as the 200ms reset delay and 20ms PBR debounce are fully internal. The LTC1326CMS8#PBF is designed for minimal external BOM while maintaining high accuracy and noise immunity.